It took me over an hour and a half but I finally beat puzzle 90. I highly doubt that the solution I stumbled across is the one the designer had in my mind. It was messy, but I'll take it. So I'm now done with the 100 main puzzles.
I had been really looking forward to playing through the prototype puzzles as I really liked the idea of structures which were more complex and which had more depth (literal depth). The prototype puzzles ended up looking really cool, but they weren't all that fun to resolve (with the exception of 'Robot 3D' which was the best of the bunch). I was very happy and surprised, therefore, to discover that after beating all 100 main puzzles you unlock a whole new area with, you guessed it, MORE PUZZLES! Although I've only played 2 of these 'latter' puzzles so far, they already seem much more engaging.
This game has a crazy amount of content, and that's not even factoring in the Studio and user created puzzles (neither of which I've even touched yet).